Carrier current control transmitter system



June 10, 19.41. WOODWQRTH 2,245,242

CARTIER CURRENT CONTROL TRANSMITTER SYSTEM Filed June 1, 194Q To CURRENT To CURRENT r- Souacz I4 SOURCE l5 3 lilo-0 --6 4- -5 M6 A A w LIJ u M 3 53 K LI LL] 3 E 0 x a. 2 2 F l- K a E J, E U. 3% E y El 8 z Q 5 & l E u 5% 3 8 M T0 POWER SOURCE TO SECOND DIS TRIBUTION LINE Inventor: John L,. Woodworbh Attorney.

Patented June 10, 1941 main @ATENT CARR-KER CURRENT CONTRQL TRANS- MITTER SYSTEM New York Application June 1,

6 Claims.

My invention relates to carrier-current systems, particularly to carrier-current control transmitters for supplying carrier-current impulses to electric lines or distribution networks, for the control, for example, of off-peak loads such as water heaters at remote points on the network.

The general object of my invention is the provision of an improved automatically operating carrier-current control transmitter arrangement for the above-mentioned and like uses.

In accordance with my invention this object is accomplished by the provision of a carrier-current control transmitter arrangement comprising means for initiating the operation, and controlling the time period of operation, of generating means for supplying the carrier-current impulses to the distribution lines in response to load conditions thereon, and means associated with the load responsive means to delay for a predetermined period the initiation of the carrier current impulses, thereby to obviate irregular or other undesired operation of the system.

The novel features which are considered to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawing, Fig. 1 of which is a diagrammatic representation of a carrier-current system embody- .ing my invention, Fig. 2 illustrates a slightly different connection arrangement for the carriercurrent system of Fig. 1, and Fig. 3 is a diagrammatic representation of a system similar to that illustrated in Figures 1 and 2 but adapted to the supplying of carrier current to two distribution lines consecutively.

Referring to Fig. 1, the numeral l designates an electric line which may form part of a distribution system or network operating at a usual commercial frequency, as60 cycles per second. This system may carry usual loads of varying amount connected to the power source continuously and also may carry off-peak loads, such as water heaters, adapted to be disconnected from the power source during peak or overload periods, or periods of heavy load above a predetermined amount, and to be reconnected thereto during underload periods.

The numeral 2 designates a carrier-current generating means, which may include a motor 3, adapted to be connected to a suitable current 1940, Serial No. 338,362

source (not shown) through leads l to E, and a generator 1 adapted to be coupled to line I by a suitable coupling means such as a coupling transformer 8 for supplying carrier-current impulses to the line at a desired frequency, for example, 720 cycles per second. These impulses may be utilized in a usual manner through suitable carrier-current responsive means (not shown) at a remote station on the line to control, automatically, the connection to the line of a Water heater (not shown) or like temporary load.

The numeral t designates a carrier-current transmitter in accordance with my invention for controlling in response to load conditions on line i the initiation of operation of the carrier-current generating means 2 included in the transmitter apparatus, and the length of the time intervals during which the generating means is connected to the line.

The transmitter 9 comprises a switch or relay means or like device ll] having an actuating winding ll energized in accordance with load conditions on line 1 preferably by connection of the winding through leads [2 to a winding l3 of coupling transformer 8, contacts i l adapted to be closed under overload or heavy load conditions above a predetermined amount, on the line i, and contacts l5 adapted to be closed under predetermined underload conditions on the line.

The transmitter 9 further comprises a switch means 55, which includes a motor generator control switch I? and a time switch, or relay, l8 associated therewith. The motor generator switch ll is provided with an actuating winding l9, the energizing means for which will be described hereinafter, contacts 2% adapted to control the connection of the motor 3 to the current source, and contacts 25 adapted to control the connection of the generator l to the coupling transformer E3. The time switch, or relay, i8 is provided with contacts 22 and 23 both connected to one of the current source leads, as E, and in series respectively through leads 24 and 25 with heavy load and underload contacts M and E5 of load responsive switch means ii]. The time switch or relay It is also provided with an actuating winding 25 the energizing means for which will be described presently.

The transmitter 9 further includes a time switch or relay means 2?, adapted to delay the energizing of the actuating winding E9 of motor generator switch ll and of the actuating winding 26 of the time switch I8. For this purpose the time switch 21 is provided with contacts 28 and 29 both connected to the paralleled actuating windings I9 and 26 and in series respectively with contacts 22 and 23 of time switch I8. The time switch 27 further includes an actuating winding 30 connected in series with contacts I4 and I5 of load responsive switch means I6. Actuating windings 30, 26, and I6, of switch means 2?, I8 and II respectively, are all connected to a lead 6 of the generating means supply source.

The total cycles or total time periods of the time switch means I8 and 21, respectively, may be approximately 50 seconds and ten minutes. In one cycle of time switch I8 the contacts preferably reverse after ten seconds and again at the end of the cycle. Time switch 21, if energized continuously, is so arranged thatit reverses its contacts after five minutes. For both time switches, however, the time periods of the contact operations are preferably adjustable overa wide range to meet particular conditions.

Referring to the circuits involving actuating winding 38 of time switch 21, one circuit includes lead 6 of the current source, the actuating winding 33, overload or heavy load contacts Id of load responsive switch I 6, contacts 22 of time switch I8, and lead 5 of the current source. The other circuit includes current source lead 6, the actuating winding 36, underload contacts I5 of load responsive switch means I6, contacts 23 of time switch I8, and current source lead 5.

Referring to the circuits involving the actuating winding I9 of the motor generator switch I1, one of thesecircuits includes current source lead 6, the actuating winding I9, contacts 28 of time switch2'l, contacts 22 of time switch I8, and current source lead 5. The other circuit includes current source lead 6, the actuating winding I9, contacts 29 of time switch 27, contacts 23 of time switch I8, and current source lead 5.

Referring to the circuits involving actuating winding 26 of time switch I3, one of these circuits includes current source lead 6, the actuating winding 26, contacts 28 of time switch 21, contacts 22 of time switch I8, and current source lead 5. The other circuit includes current source lead 6, the actuating winding 26, contacts 29 of time-switch 21, contacts 23 of time switch means I8, and current source lead 5.

In the embodiment of my invention illustrated in Fig. 1 the coupling transformer 8 operates to supply carrier current at 720 cyclesper second through blocking capacitors 3| to the power line I from generator I as well as to supply energizing current at 60 cycles per second from the power line I to the actuating Winding II of load responsive relay II). Coupling transformer 8 is in series resonance connection with the blocking capacitors 3| which are in series with the generator I. A relatively high voltage at carrier frequency therefore appears across winding I3 of the coupling transformer 8. Under some conditions this high carrier voltage may adversely affect the calibration of relay I0. To prevent this result it is desirable to provide a wave trap,

in the circuit of transformer winding I3 and relaywinding II, comprising an inductance 32 and a capacitor 33 in parallel resonance connection. The wave trap prevents the 720 cycle carrier current from-flowing in the circuit including relay winding II but permits the 60 cycle line current to flow in this circuit through the inductance element 32.

Instead of energizing actuating winding II of relay I0 by connection to a winding I3 of coupling transformer 8 as shown in the drawing, a separate current transformer (not shown) associated with the power line I in a usual manner may be employed. In this case the trap circuit 32, 33 would not be required because the current transformer would not function as part of the above-mentioned resonant circuit including blocking capacitors 3|, and, therefore, the high carrier voltage would not be impressed on the current transformer.

In operation, let it be assumed that the various switch means of the carrier-current control transmitter 9 are initially in their illustrated positions. corresponding to a continuing condition of overload or heavy load on line I. During the condition of overload or heavy load, contacts I4 of the load responsive switch means III are in closed position and underload contacts I5 are open, the switch It being maintained in this position by the current in winding II which is supplied from coupling transformer winding I3 and which corresponds to the relatively heavy load on line I. Contacts 26 and 2I of motor generator switch IT are open, thereby maintaining motor 3 disconnected from its current source and generator I disconnected from the coupling transformer 8. Contacts 23 and 28 of switch means I8 and. 21 respectively are in closed position and contacts 22 and 29 are open. One of the circuits of the paralleled actuating windings I9 and 26 although closed at contacts 23 of switch I8 is open at contacts 29 of switch means 21, and the other circuit of paralleled windings I 9 and 26 although closed at contacts 28 of switch 2'! is open at contacts 22 of switch I8. Likewise one of the circuits of actuating winding 30 although closed at contacts I I of load responsive switch I6 is open at contacts 22 of switchI8, and the other circuit of winding 30 although closed'at contacts 23 of switch I8 is open at contacts I5 of load responsive switch III.

Actuating windings I9, 26, and 36 of the switch means I'I, I8 and 21 respectivelyare, therefore, all in deenergized condition, the carrier-current control transmitter system is in shut down condition, and no carrier-current is being transmitted sponse to the underload condition on line I the underload contacts I5 'of load responsive switch means In are caused to close and the overload or heavy load contacts I 4 are opened. The actuating winding 30 of switch 21 is energized through contacts I5 of switch I0 and contacts 23 of switch I8 as soon as the load responsive switch I 9 is actuated to the underload position, but the energizing of actuating windings I 9 and 26 of switches I! and I8 is prevented until the time switch 21, after the energizing of its actuating winding 30, operates to reverse its contacts. Preferably this delay period is relatively long, five minutes for example.

As soon as the contacts of switch 2! reverse, thereby opening contacts 28 and closing contacts 29, actuating windings I9 and 26 of switches I1 and I8 are energized through the contacts 29 of the switch 21 and contacts 23 of switch I8. Motor generator switch I! is immediately operated to closed position by winding I9 to connect motor 3 to its current source and. generator I to its coupling transformer 8. Approximately one second The positions illustrated are those later, for example, the motor generator is up to speed and in operative condition and the transmission of a carrier current impulse on line I is initiated. After a relatively short time interval, ten seconds for example, time switch I8 operates toreverse its contacts thereby closing contacts 22 and opening contacts 23. Actuating winding IQ of motor generator switch I! is then immediately deenergized, the motor generator is disconnected from the current source and also from the coupling transformer 8, and the transmission of the carrier-current impulse is stopped.

It will be understood that this relatively short carrier impulse, thus limited in the present case to a period of ten seconds, may be utilized by suitable impulse responsive means (not shown) on line I to turn on a heater (not shown) or other like load.

The carrier-current control system is now in underload shut down condition and remains in this condition, with contacts 2|, 2!), 23, 28 and M open and contacts 22, 29 and I closed, as long as the underload obtains on line l.

Assuming that after a period of underlcad the load on line I increases to a predetermined value, corresponding to an overload or a relatively heavy load, then in response to the heavy load condition the overload or heavy load contacts M of load responsive switch means are caused to close and the underload contacts I5 are opened. Winding 34) of switch 21 is energized, through contacts M of switch Ill and contacts 22 of switch I8, immediately following actuation of switch H! to the overload or heavy load position. Energizing of windings l9 and 26 is, however, prevented until time switch 21 operates to reverse its contacts, for example after the time period of five minutes.

Immediately following the reversal of switch 21 thereby opening contacts 29 and closing contacts 28, actuating windings l9 and 26 are energized through the contacts 28 of the switch 21 and contacts 22 of switch Hi. The transmission of another carrier-current impulse from generator I on line I is then initiated, as hereinbefore described. After a time interval which, as before, may be relatively short but of a different length from the short impulse first mentioned, 39 seconds for example instead of ten seconds, time switch !8 operates to reverse its contacts thereby closing contacts 23 and opening contacts 22. Actuating winding IQ of motor generator switch I1 is again deenergized and transmission of the carrier-current impulse is stopped.

Similarly to the ten second impulse before mentioned, the second impulse, limited to a different period, as 39 seconds, may be utilized by suitable impulse responsive means to turn ofi the heater or like temporary load from line I.

After the cycle of switching of the apparatus as above described the carrier-current control system is again in shutdown condition with the various switch means in their initial positions illustrated in the drawing. The described switching cycle of the apparatus may be repeated indefinitely in response to the recurring heavy load and underload conditions on the distribution line.

Referring to Fig. 2, the circuit elements and circuit arrangements of the carrier current system illustrated therein are the same as in the system of Fig. 1 except for the circuit connections of actuating windings I9, 26 and 3E], and of contacts l4 and i5 of load responsive relay It].

In Fig. 2, one of the circuits involving the actuating winding 38 of relay l0 includes current source lead 6, the winding 30, overload contacts H of relay Ill, contacts 29 of relay 21 instead of contacts 22 of relay [8, and current source lead 5. The other circuit involving winding 39 includes lead 6, the winding 30, underload contacts l5 oi relay Hi, contacts 28 of relay 2? instead of contacts 23 of relay [8, and lead 5. The circuits involving the paralleled actuating windings l9 and 25, of switch 19 and relay l3 respectively, are the same as in the corresponding circuits of Fig. 1 except that in Fig. 2 the contacts 22 and 23 01 relay [8 and contacts 28 and 29 of relay 2'! are connected in a sequence different from the sequence in which they are connected in Fig. 1.

The switching cycle of the apparatus of Fig. 2 is substantially the same as set forth hereinabove in connection with the system of Fig. 1, the switching operations in the two systems difiering only in that in the system of Fig. 2 actuating coil 30 of load responsive relay It is energized through the contacts of relay 2! instead of through the contacts of relay l8.

Referring to Fig. 3, in the system therein illustrated, in addition to the means hereinabove described for controlling oiT-peak loads on one distribution line, means are provided for controlling the loads on two such lines in succession. To supply carrier-current impulses to the second distribution line, a second transformer 34 and a motor generator switch means 35 having an actuating winding 36, contacts 31 for connecting the carrier current generator I to the transformer 34 and contacts 38 for connecting the motor 3 to its current source, are provided.

To control the initiation and time period of operation of the generating means 2 when supplying carrier current impulses to the second distribution line, a time switch 39 having contacts 6!! and M and an actuating winding 42 is provided adapted to cooperate with actuating winding 38 of motor generator switch 35 in essentially the same manner that time delay relay is cooperates as hereinbcfore described with actuating winding is of motor generator switch ii.

To delay the initiation of the supplying of carrier-current impulses to the second distribution line until, during a given cycle, the initiation and timing of a carrier-current impulse to the first distribution line has been accomplished, a

switch means, as switch contacts 23, is provided adapted to be operated by the actuating coil IQ of motor generator switch ll. The switch means 43 is arranged to control the supply of operating current to actuating winding of motor generator switch 35 and actuating winding 42 of time switch 39.

In Fig. 3 the circuits involving actuating winding 38 of time switch 21, actuating winding IQ of motor-generator switch ll, and actuating winding 26 of time switch l8 are preferably the same as illustrated, for example, in the system of Fig. 2.

Referring to the circuits involving the actu ating winding 35 of the motor generator switch 35, one of these circuits includes current source lead 6, switch contacts 33, the actuating winding 36, contacts 43 of time switch 38, contacts 29 of time switch 2'1, and current source lead 5. The other circuit includes current source lead 6, switch contacts t3, the actuating winding 35, contacts il of time switch 39, contacts 23 of time switch 2?, and current source lead 5.

Referring to the circuits involving the actuating winding &2 of time switch 39, one of these circuits includes current source lead 6, switch contacts 43, the actuating winding G2, contacts 40 of time switch 39, contacts 29 of time switch 21, and current source lead5. The other circuit includes current source lead 6, switch contacts 43, the actuating winding 42, contacts 4| of time switch 39, contacts 28' of time switch 27, and current source lead 5.

To energize the actuating winding II of switch or relay means I!) in accordance with load conditions on the distribution lines, a current transformer M associated with the connections to the distribution lines power source is preferably provided.

In operation of the system illustrated in Fig. 3, let it be assumed that the several switch means are initially in their illustrated positions, corresponding to a continuing condition of overload on the distribution lines. The illustrated shut down condition of the system of Fig. 3 persists during the continuance of the overload on the distribution lines.

Assuming that an underload now occurs on the distribution lines, load responsive switch I 3 opens contacts I4 and closes contacts I 5. At the end of a five minute period switch 21 opens contacts 28 and closes contacts 29, and actuating winding I9 is energized and closes motor generator switch contacts 20 and 2| thus starting the generation of carrier current impulses. After approximately one second the generator is up to speed and carrier-current impulses are impressed on the first distribution line through transformer 8. Simultaneously with the energizing of winding I9, winding 26 of time switch I8 is also energized. After a ten second period, the switch I3 operates to close contacts 22 and to open contacts 23, thus deenergizing winding I9.

At the instant winding I9 is deenergized, contacts 20 and El of switch I! are opened. The

opening of contacts 2I disconnects transformer 8 from the generator 'I and stops the impressing of carrier current impulses upon the first distribution line. Simultaneously with the opening of contacts Ziland 2| of the motor generator switch H, the switch contacts 43 are operated to closed position since contacts 43 are also actuated by winding I9. Actuating winding 33 of the other motor generator switch 35, is then immediately energized, the circuit being from lead 6, through contacts 43, the winding 36, contacts 43 of time switch 39, and contacts 29 of switch 27, to lead 5. Contacts 31 and 38 of the motor generator switch 35 close, immediately reconnecting motor 3 to its power source and connecting generator I to the transformer 34 thereby initiating the supplying of carrier current to the second distribution line. After a time period of ten seconds,

time switch 39 reverses its contacts, closing contacts 4| and opening contacts 43. Actuating winding 36 of motor generator switch 35 is then deenergized, causing contacts 38 and 3'! to reopen to disconnect motor 3 from its current source and to disconnect generator 1 from the transformer energized. Contacts 20 and ZI of switch I! are caused to close thereby initiating the impressing of carrier current on the first distribution line, and contacts 33 are caused to open thereby preventing the energizing of actuating winding 36 of switch 35 and preventing the supplying of carrier current to the second distrbiution lines.

After a time period of thirty-nine seconds, time switch 93 reverses its contacts, closing the contacts 23 and opening the contacts 22.- Actuaating winding H of switch I! is immediately deenergized, switch I'I opens thereby stoppingv the impressing of carrier current upon the first distribution line, and contacts 43 are caused to close. Upon the closing of contacts 63, actuating Winding 36 of switch 35 is energized, and contacts 38 and 3'! close thereby initiating the impressing of carrier-current upon the second distribution line.

After a time period of thirty-nine seconds, time switch 39 reverses its contacts, closing contacts as and opening contacts ti, thus deenergizing the actuating winding 36 of switch 35 and thereby stopping the impressing of carrier-current upon the sec nd distribution line, The entire system of Fig. 3 is now in overload shutdown condition, with the various parts of the apparatus again in their illustrated positions.

It will be apparent that the circuit arrangement of Fig. 3 may be readily expanded to permit energizing not only of two distribution lines as shown but of any desired number of distribution lines or feeders in succession.

It will be noted that in the hereinabove described carrier-current control transmitter systration. It will be understood, however, that the invention is susceptible of various changes and modifications and that by the appended claims I intend to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an electric system including means for generating carrier-current and for impressing said carrier-current on an electric line, switch means adapted to initiate operation of said generating means for predetermined time intervals in response to a change in load condition on said line, and switch means adapted to prevent said initiation of operation of said generating means by said first-named switch means until after a predetermined time interval following said change in load condition.

2. In a carrier current system including an electric line and means for generating said current and for impressing said current upon said line, switch means responsive to a load condition on said line, switch means adapted in cooperation with said load responsive switch means to initiatev operation of said generating means and to stop said operation after predetermined time intervals, and switch means operatively associated with said load responsive switch means to prevent said initiation of operation of said generating means by said second-named switch means until after a predetermined time interval.

3. In a system for impressing carrier-current on an electric line, means for generating said carrier-current, a current source, switch means responsive to a load condition on said line, switch means adapted in cooperation with said load responsive switch means to be energized from said source to initiate operation of said generating means and to stop said operation after predetermined time intervals, and switch means adapted to be energized from said source through said load responsive switch means to prevent said initiation of operation of said generating means by said second-named switch means until after a predetermined time interval.

4. In a carrier current system including an electric line and means for generating said current and for impressing said current upon said line, switch means responsive to underload conditions and to heavy load conditions on said line, switch means adapted in cooperation with said load responsive switch means to initiate operation of said generating means and to stop said operation after different predetermined time intervals under said underload and heavy load conditions respectively, and switch means operatively associated with said load responsive switch means to prevent said initiation of operation of said generating means by said secondnamed switch means until after a predetermined time interval.

5. In a carrier current system including an electric line and means for generating said current and for impressing said current upon said line, switch means responsive to a load condition on said line, a current source, switch means adapted to he energized from said source through said lead responsive switch means to connect said generating means to said source and to disconnect generating means from said source after a predetermined time interval, and switch means adapted to be energized from said source through said load responsive switch means to prevent said. connecting of said generating means to said source by said second-named switch means until after a p edetermined time interval.

6. A carrier-current system including at least two electric dis oution lines, means for generating said carrier-current, means for impressing said current upon said lines, switch means respcnsive to a load condition on said lines, switch means adapted in cooperation with said load responsive means to initiate and to time the supplying of carrier-current from said generating means to said distribution lines in succession, and switch means operatively associated with said load responsive switch means to prevent said initiation and timing of the supplying of carrier current until after a predetermined time interval.

JOHN L. WOODWORTH 

